1. Technical Field
The present invention relates to a cassette that has a tray, which contain medium, such as sheets of paper, and that is mounted on an image forming apparatus in order to supply the media and an image forming apparatus that is provided with the cassette.
2. Related Art
In an existing art, a cassette-type paper feeding system in which a cassette that loads and contains sheets of paper as media is mounted on a printer body to feed paper is known as a paper feeding system of a printer, which is an image forming apparatus of this type. The cassette contains one type of sheet of paper. When the paper size is changed, the cassette needs to be manually replaced. In addition, there is known a feeding system that is provided with a divider for each paper size in the tray of a cassette in order to be able to support multiple types of paper size, which is, for example, described in JP-A-2002-321838.
The printer body is provided with a pick-up roller so that the pick-up roller is arranged to be contactable on the upper face of sheets of paper loaded on the cassette in a state where the cassette is mounted, and an uppermost sheet of paper is delivered from the cassette in such a manner that the pick-up roller is driven for rotation. At this time, multiple sheets of paper may possibly be delivered in a state where lower side sheets of paper overlap the uppermost sheet of paper; however, the distal ends of the sheets of paper abut against the oblique surface of a separation plate (separation portion) that extends from the downstream end in the paper feeding direction of the cassette, so that only the uppermost sheet of paper is separated from the lower side sheets of paper and the separated sheet of paper is guided along the oblique surface of the separation portion to thereby be delivered, for example, upward, which is, for example, described in JP-A-2002-321838.
Incidentally, it is conceivable that a cassette structure is provided so that a plurality of trays are provided multiply in a cassette so as to be capable of containing multiple types of sheets of paper having different paper types or sizes. In this case, it is conceivable that sheets of paper that are delivered from an upper tray is separated by having it abut against the oblique surface of the separation plate that extends from the end of a lower tray and, in this manner, the separation plate is shared between the trays. However, the type and/or size of a sheet of paper loaded on each tray is different from each other. For example, if the tray is an A4 size tray, “plain paper” is normally used. On the other hand, if the tray is a tray that contains a small size sheet of paper of which the paper size is about L size or 2L size, “photo paper” or “postcard” is normally used.
If the sheet of paper is thin and flexible like “plain paper”, it is apt to bend. Thus, if the sheet of paper can be separated so that the distal end of the sheet of paper abuts against the oblique surface of the separation portion, even when the angle of inclination of the oblique surface is somewhat large, the sheet of paper may be guided in a substantially vertical direction. However, when the angle of the oblique surface is relatively small, the sheet of paper cannot be separated. In this case, a lower side sheets of paper together with the uppermost sheet of paper is also delivered. This leads to a multi feeding error that multiple sheets of paper are fed. In the meantime, in the case of a hard sheet of paper, such as “photo paper” or “postcard”, when the distal end of the sheet of paper abuts against the oblique surface of the separation portion, it is possible to be separated even when the angle of the oblique surface is somewhat large; however, because the sheet of paper is not easy to bend, it is difficult to guide the sheet of paper along the large-angled oblique surface in a substantially vertical direction. In this case, this leads to a paper feeding error that the sheet of paper is not delivered. Therefore, in the cassette that has multiple trays, when the separation portion is shared among the trays, there has been a possibility that inconvenience that separation of sheets of paper or guiding of the separated sheet of paper in a paper feeding direction is not appropriately performed in each tray may occur.